This invention relates generally to fire extinguisher systems, and more particularly, to a check valve arrangement for facilitating periodic maintenance of the pressure monitoring and actuation systems in a chemical fire extinguisher system.
Pressurized chemical fire extinguisher systems generally are triggered into operation by release of pressure on an ambient side of a piston valve. This action results in displacement of the piston valve in response to the pressure in the chemical storage tank, and subsequent opening of the piston valve. The piston valve remains in the closed state as long as the ambient side remains sealed, whereby the pressure on both sides of the piston is equalized. The ambient side pressure is reduced by venting the ambient side of the piston to the atmosphere.
Venting of the piston valve may be achieved by any of several known arrangements. One known arrangement is a manually actuated valve which opens to the atmosphere upon manipulation of a control member. Alternatively, venting may be achieved by an electric valve or a pneumatic operator. In certain systems, such opening is responsive to excessive heat in the region which is desired to be protected.
In most presently known pressurized chemical fire extinguisher systems, it is extremely important that the pressure in the chemical reservoir, or tank, be monitored, as even slow leakage will eventually render the fire extinguisher system unusable and unsafe. For this reason, the tank is provided with a pressure gauge, which will provide a visual indication of the pressure in the system.
It is a problem with visual indicator gauges that after they have been exposed to a constant pressure for a considerable length of time, as is the case with fire extinguisher systems, a mechanical indicator therein may become fixed in its position, and remain indicating falsely that the fire extinguisher system is in an operational state, even though leakage may have reduced the tank pressure to an unacceptably low level. Additionally, the pressure gauge might be damaged by accidentally being struck with an object, requiring replacement or repair of the gauge. It therefore is highly desirable to service the pressure indicator periodically, and ascertain whether it is operative.
The manual operator, the electric solenoid operator, the electric low cylinder pressure switch, and the pneumatic operator are all subject to cylinder pressure and require servicing to ascertain they are all operating as intended. In the present state of the art, these assemblies cannot be checked for operation while they are subjected to cylinder pressure. It would be desirable, however, to service these assemblies without requiring depressurization, or discharge, of the cylinder. In addition to the cost and time involved in the servicing of the pressure indicator, the system is not functional during such maintenance, leaving the premises unprotected unless a replacement chemical tank is made available during servicing.
It is, therefore, an object of this invention to provide a simple and economical arrangement for facilitating periodic maintenance of a chemical fire extinguisher system.
It is another object of this invention to provide a system for providing maintenance to the pressure monitoring system of a chemical fire extinguisher without disabling the system even temporarily.
It is also an object of this invention to provide a simple apparatus for facilitating removal and replacement of a pressure gauge, electric solenoid, low cylinder pressure switch, and manual and pneumatic operators.
It is a further object of this invention to provide a safety arrangement for a chemical fire extinguisher whereby removal of a safety nut for gaining access to the pressure monitoring system of the fire extinguisher will cause discontinuation of the communication between the pressure monitoring system and the pressurized chemical.
It is additionally an object of this invention to provide a safety-check system for a fire extinguisher which is modular in construction, whereby individual components thereof are easily replaceable.
It is yet a further object of this invention to provide a system which simplifies, and reduces the cost of, servicing a chemical fire extinguisher system.